1. Field
The following description relates to a mobile communication service, and more particularly, to a technique for configuring a broadcasting zone to provide a broadcasting service.
2. Description of the Related Art
A broadcast service is one of representative wireless communication services. Generally, the broadcast service is serviced in a unicast manner meaning 1:1 data transmission between a broadcast server and a subscriber (or a mobile terminal), or in a multicast and broadcast manner meaning 1:N data transmission between a broadcast server and subscribers. The wireless communication services are expensive than wired communication services due to limitation of resource amount allocatable to subscribers. In order to provide a plurality of users with a broadcast service through a mobile communication system, a multicast and broadcast service (hereinafter, simply referred to as a MBS) which can transmit broadcast content to a plurality of users through a single resource has been used.
The IEEE802.16e, IEEE802.16m, 3GPP/LTE, and WiMAX Forum have suggested MBSs named E-MBS (Enhanced-MBS), MBMS (Multicast Broadcast Multimedia Service), E-MBMS (Enhanced-MBMS), and MCBCS (MultiCast BroadCast Service).
According to the IEEE802.16e and IEEE802.16m, all base stations grouped into a broadcast service region use the same radio resource to transmit broadcast content to terminals managed by the base stations. Such a broadcast service region is defined as a MBS or E-MBS zone.
FIG. 1 shows an example of a MBS zone defined in the IEEE 802.16e and IEEE 802.16m. In the example of FIG. 1, the MBS zone is not changed after it is once configured, and base stations (for example, 19 base stations configuring a MBS zone A) belonging to a specific MBS zone always should be allocated a channel resource for MBS. Accordingly, the base stations belonging to the MBS zone A are always allocated an expensive radio resource even when there is no terminal that receives the MBS from the base stations, which results in the waste of radio resource. The waste of radio resource becomes significant in proportion to the area of the MBS is zone.
Meanwhile, a terminal has the improved quality of received signal when receiving the same signal repeatedly. As such, combining signals coming from different sectors to improve the quality of received signal is called Macro Diversity. The quality of received signal is better when the corresponding terminal stays in the center of the MBS zone than when it is located in the edge region of the MBS zone. Accordingly, in the case where a terminal stays in the edge region of a MBS zone, the Macro Diversity effect deteriorates so that the quality of received signal becomes non-uniform. Also, if a certain user moves from a MBS zone to another MBS zone, that is, as illustrated in FIG. 1, if the user moves from the MBS zone A to a MBS zone B, service disruption occurs, which may cause the user's dissatisfaction with MBS.
Meanwhile, a Korean Laid-open Patent Application No. 10-2009-0039223 discloses an apparatus and method for managing zone for MCBCS in wireless communication system.